The present invention relates to electronic packaging and more specifically to an electronic card for use in card-on-board packaging.
Electronic card assemblies are typically fabricated from alternating layers of copper and epoxy glass, laminated together to form a sandwich of conductive and insulating materials. The resulting cards are very rigid which is desirable in many applications. The cards are mounted, typically with a fixed spacing between adjacent cards, through connectors to a planar board. Alternatively, the printed circuit card can be mounted between two boards with zero insertion force connectors serving the dual function of channel guides and electrical connectors. As used herein the term planar board refers to a panel made of insulating material that has circuits, electronic components, and connectors on the panel. A board, also referred to as backplane, is a panel which has connectors but does not have electronic components.
Difficulties can arise when a card needs to be upgraded for reasons of cost reduction, reliability improvements or adding additional function, since the card design is limited by the original spacing between adjacent cards. Most components, except for long lead items such as capacitors which can be bent to avoid adjacent obstructions, are rigidly mounted on circuit cards and do not allow positional adjustment to avoid interference with adjacent cards. If a heat sink or additional memory were required on a replacement card it might not fit in the spacing available, necessitating board or planar board redesign.
It is an object of the present invention to provide electronic card assemblies which eliminate many space restrictions imposed when modifying existing card-on-board designs.